Missouri Employer Payroll — MO-941, MO-W-3, MODES-4-7 & Local E-Tax

Confirm the employer is properly registered with the Missouri Department of Revenue (DOR) for withholding and with the Division of Employment Security (DES) for UI. Obtain the employer's FEIN, Missouri withholding account number, and UI account number. Determine whether any work locations fall within Kansas City or St. Louis city limits, which triggers additional registration obligations with those cities' Revenue Divisions.

Collect and process a signed Missouri Form MO W-4 from every employee performing services in Missouri. Missouri does NOT accept the federal Form W-4 as a substitute. Verify filing status, allowances (from the MO W-4's own allowance worksheet — not the federal allowance count), any exempt claims, and MSRRA elections for nonresident military spouses. Default any employee who fails to submit a MO W-4 to Single / zero allowances.

Determine the employer's MO-941 filing frequency (annual, quarterly, monthly, or quarter-monthly) based on the DOR's lookback-period notice for 2025. Compute per-payroll withholding using the 2025 MO PIT brackets (top rate 4.95%) and confirm supplemental wages are handled via either the aggregate method or the 4.95% flat rate. EFT is mandatory if annual withholding is $8,000 or more. File MO-941 returns on the assigned cadence via MyTax Missouri.

Compute quarterly MO UI contributions using the employer's DES-assigned experience rate (0.0%–9.75%; new non-construction employers at 2.7%) applied to the $9,500-per-employee taxable wage base for 2025. File the quarterly Contribution and Wage Report (Form MODES-4-7 or UInteract equivalent) by the last day of the month following each quarter close. Evaluate whether a voluntary contribution by January 15 would reduce the experience rate for the following year.

For each employee performing services within Kansas City corporate limits (Jackson, Clay, Platte, or Cass County portions — verified via kcmo.gov address lookup, not ZIP code), withhold the 1% KC E-Tax and file Form RD-110 quarterly or RD-130 monthly depending on volume, plus the annual Form RD-113 reconciliation by February 28, 2026. For each employee performing services within City of St. Louis corporate limits (distinct from St. Louis County — verified via stlouis-mo.gov), withhold the 1% St. Louis E-Tax and file Form W-10 quarterly plus Form W-11 annual reconciliation by January 31, 2026. Apply Boles v. City of St. Louis (Mo. Ct. App. 2023): withhold only on actual city-work days, not on remote days even if the employer's office is in the city.

Prepare and file Form MO-W-3 (Annual Transmittal) reconciling total Missouri wages and withheld tax against all MO-941 returns filed for 2025, together with Copy 1 of each W-2 (or EFW2 electronic file for employers issuing 250+ W-2s), due January 31, 2026. File the KC annual reconciliation Form RD-113 by February 28, 2026, and the St. Louis annual reconciliation Form W-11 by January 31, 2026. File the Q4 MODES-4-7 by January 31, 2026. Perform the 12-point reviewer self-check (Form 4282 rate confirmation, MO W-4 completeness, filing-frequency match, UI rate notice, city-limits address verification, etc.).